Modern long-haul passenger aircraft are usually equipped with rest rooms for the crew, to which the crew-members can retire during the flight. In these rest rooms for the crew, beds are provided in which a surface for lying on is formed by a mattress made of latex or foam which is supported on a corresponding, suitable under-frame. Beds of this kind are relatively heavy. Furthermore, because of the fact that the mattresses have to be used by many different people, it is not possible to adapt the characteristics of use, and particularly the firmness of the mattresses, to the perceptions of individual users as regards comfort.
From EP 1 207 074 B1, a passenger seat which is suitable for use in an aircraft and which has a backrest that can be adjusted between a sitting position and a lying position, is known. A seating surface springing system of the passenger seat comprises rotatably mounted seat lamellae. By rotating the seat lamellae, it is possible to vary the stiffness per unit area of the seating surface in dependence upon the position of the backrest.